JP7049124B2 - Universal joint yoke - Google Patents

Description

The present invention relates to a universal joint yoke, and more particularly to a universal joint yoke used for a cross-axis universal joint (cardan joint).

A universal joint is provided between two shafts arranged at different angles to transmit the rotation of one shaft to the other shaft. The universal joint has two yokes, and the yokes are connected to each other by a cross axis.

The universal joint yoke comprises, for example, a substantially cylindrical base and a pair of arms extending axially from one end of the base. The base has serration holes and slits. The serration holes penetrate the base axially. The slit extends radially and penetrates the serration hole and the outer peripheral side surface of the base.

In the universal joint yoke, a screw hole is formed which is in a twisted position with respect to the central axis of the serration hole and extends in a direction substantially perpendicular to the central axis of the serration hole. With one end of the shaft inserted in the serration hole, insert the bolt into the screw hole. When the bolt is inserted into the screw hole, the base is elastically deformed so that the distance between the slits is narrowed. As a result, one end of the shaft inserted into the serration hole is tightened by the base, so that the shaft is joined to the yoke.

In a universal joint yoke, the amount of elastic deformation of the base decreases as the rigidity against deflection at the base increases. Normally, the inner diameter of the serration hole is larger than the outer diameter of the shaft. Therefore, when the amount of elastic deformation of the base is small, it becomes difficult for the base to be deformed so that the inner diameter of the serration hole becomes small. That is, the base cannot sufficiently obtain the contact area between the base and the shaft, and the shaft cannot be sufficiently tightened. As a result, the joint strength between the yoke and the shaft may be insufficient.

On the other hand, since the yoke rotates together with the shaft, it is required to increase the rigidity against the torsional force generated by the rotation of the shaft.

Japanese Unexamined Patent Publication No. 2016-38033 (Patent Document 1) discloses a yoke for a universal joint. A recess is formed in the universal joint yoke. The recess is formed from the outer peripheral side surface of the base portion to the arm portion of the pair of arms on the side where the slit is formed. The recess is formed in the radial outer opening of the slit and extends axially. By forming the recess, the rigidity against the deflection at the base can be lowered to increase the tightening force, and the rigidity against the torsional force at the base can be secured.

Japanese Unexamined Patent Publication No. 2016-38033

An object of the present invention is to provide a universal joint yoke capable of ensuring rigidity against a torsional force and reducing rigidity against bending.

The universal joint yoke of the present disclosure is a universal joint yoke having a base and a pair of arms extending axially from the other end of the base in the axial direction, and the base portion has a connecting hole in the axial direction. To sandwich a cylindrical portion through which the shaft is inserted into the connecting hole from one end in the axial direction, and a slit penetrating the inner peripheral surface of the tubular portion and the outer peripheral side surface of the tubular portion. It is provided with a pair of tightening plates arranged so as to face each other and projecting radially outward from the outer peripheral side surface of the tubular portion, and a recess formed on the radial outer surface of the base portion.

According to this, since the concave portion is formed on the outer peripheral surface of the base portion, the tightening force on the shaft in the tubular portion is increased, and the rigidity of the universal joint yoke is ensured while ensuring the rigidity of the universal joint yoke. The rigidity against deflection can be reduced.

Further, the end portion on one side in the axial direction of the slit extending in the axial direction is opened at one end surface in the axial direction of the tubular portion, and the other end portion in the axial direction is a pocket surface between a pair of arms. The other end of the recess in the axial direction may be located on one side of the pocket surface.

According to this, while maintaining high rigidity of the joint portion between the base portion and the arm portion, it is possible to reduce the rigidity against bending of the tubular portion due to the axial force generated by tightening the tightening bolt.

Further, the inner peripheral surface of the connecting hole is provided with serrations extending in the axial direction, and a counterbore portion without serrations is provided on the inner circumference of the other end of the connecting hole in the axial direction, and the shaft of the recess is provided. Direction The other end may be located on one side of the counterbore.

According to this, it is possible to alleviate the concentration of stress generated in the counterbore portion having a diameter larger than that of the connecting hole.

Further, the recess may be opened at one end surface of the base portion in the axial direction. According to this, a universal joint yoke having a recess can be easily manufactured by forging.

Further, the first recess, which is one of the recesses, may be formed on the radial outer surface of the tightening plate. Further, the first recess may be formed in both of the pair of the tightening plates and may be opened on the facing surfaces of the tightening plates.

According to this, it is possible to easily reduce the inner diameter of the tubular portion by the axial force of the tightening bolt while maintaining the rigidity of the tubular portion at a high level and ensuring the rigidity against the torsional force.

Further, a bolt insertion hole formed from the tubular portion to the tightening plate is further provided, and the first recess is gradually deepened from the other side of the central axis of the bolt insertion hole toward the other in the axial direction. May decrease.

According to this, it is possible to suppress the strain generated when the distance between the pair of tightening plates is narrowed by the axial force of the tightening bolt.

According to the universal joint yoke according to the present disclosure, it is possible to reduce the rigidity of the universal joint yoke with respect to bending while ensuring the rigidity of the universal joint yoke with respect to torsion.

It is a schematic diagram which shows the structure of the steering apparatus using the yoke which concerns on 1st Embodiment of this invention. It is a figure which shows the connection state of the intermediate shaft shown in FIG. It is a perspective view of the yoke joined with the steering shaft shown in FIG. It is a front view of the yoke shown in FIG. It is a top view of the yoke shown in FIG. It is a side view which looked at the yoke shown in FIG. 3 from one axial direction to the other axial direction. It is a perspective view of the yoke which concerns on 2nd Embodiment of this invention. It is a perspective view of the yoke which concerns on 3rd Embodiment of this invention. It is a side view which looked at the yoke shown in FIG. 8 from one axial direction to the other axial direction.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding parts in the figure are designated by the same reference numerals and the description thereof will not be repeated. For convenience of explanation, in each figure, the configuration may be simplified or schematically shown, or some configurations may be simplified and shown.

In addition, all of the embodiments described below show comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components, steps, the order of steps, and the like shown in the following embodiments are examples, and are not intended to limit the present invention. Further, among the components in the following embodiments, the components not described in the independent claim indicating the highest level concept are described as arbitrary components.

Further, the drawings are schematic views in which emphasis, omission, and ratio adjustment are appropriately performed to show the present invention, and may differ from the actual shape, positional relationship, and ratio.

{1. Configuration of steering device 100}
FIG. 1 is a schematic view of a steering device 100 using a yoke according to the first embodiment of the present invention. With reference to FIG. 1, the steering device 100 is mounted on a vehicle such as an automobile. The steering device 100 includes a steering wheel 1, a steering shaft 2, an intermediate shaft 3, a pinion shaft 4, a pinion 5, a rack 6, tie rods 7, 7, and universal joints 10A, 10B.

In the following description, the extending direction of the intermediate shaft 3 is defined as the vertical direction. The upward direction is the direction in which the steering shaft 2 is located when viewed from the intermediate shaft 3. The downward direction is the direction in which the pinion shaft 4 is located when viewed from the intermediate shaft 3.

The upper end of the steering shaft 2 is connected to the steering wheel 1, and the lower end of the steering shaft 2 is connected to the upper end of the intermediate shaft 3 by a universal joint 10A. The lower end of the intermediate shaft 3 is connected to the upper end of the pinion shaft 4 by a universal joint 10B.

A pinion 5 is connected to the lower end of the pinion shaft 4. The pinion 5 rotates in conjunction with the operation of the steering wheel 1 by the driver of the vehicle. The rack 6 extends in the lateral direction of the vehicle (direction in which the rack 6 extends) and meshes with the pinion 5.

The rotational motion of the pinion shaft 4 is converted into a linear motion of the rack 6 by the pinion 5 and the rack 6. That is, the rack 6 moves laterally to the vehicle due to the rotation of the pinion shaft 4. The vehicle is steered by the tie rods 7 and 7 pushing and pulling the rolling serpentine wheels 8 and 8 of the vehicle in response to the lateral movement of the rack 6.

{2. Configuration of universal joints 10A and 10B}
FIG. 2 is a diagram showing a connection state between the steering shaft 2 and the intermediate shaft 3 shown in FIG. 1 and a connection state between the intermediate shaft 3 and the pinion shaft 4.

With reference to FIG. 2, the universal joint 10A is a cross-axis universal joint (cardan joint) and includes yokes 11A and 12A and a cross-axis 13A. The yoke 11A is joined to the lower end of the steering shaft 2 by being tightened by the tightening bolt 14A. The yoke 12A is joined to the upper end of the intermediate shaft 3. The joining of the yoke 12A and the intermediate shaft 3 is performed, for example, by welding. The yokes 11A and 12A are connected by a cross shaft 13A.

The universal joint 10B is a cross-axis type universal joint, and includes yokes 11B and 12B and a cross-axis 13B. In the present embodiment, the universal joint 10B uses two types of yokes, yokes 11B and 12B, of which the yoke 11B is the yoke according to the present invention. The yoke 11B is joined to the upper end of the pinion shaft 4 by being tightened by the tightening bolt 14B. The yoke 12B is joined to the lower end of the intermediate shaft 3. The joining of the yoke 12B and the intermediate shaft 3 is performed, for example, by welding. The yokes 11B and 12B are connected to the cross shaft 13B, respectively.

The structure of the yoke 11B used in the universal joint 10B is the same as the structure of the yoke 11A used in the universal joint 10A. Therefore, in the following description, the yoke 11A will be described in detail, and the description of the yoke 11B will be omitted.

[First Embodiment]
{3. Configuration of universal joint yoke 11A}
FIG. 3 is a perspective view of the yoke 11A shown in FIG. With reference to FIG. 3, the yoke 11A comprises a base 21 and arms 22 and 23.

With reference to FIG. 3, the direction in which the central axis CL extends is referred to as an axial direction, and the direction perpendicular to the central axis CL is defined as a radial direction. Of the axial directions, the right side of the paper surface in FIG. 3 is defined as one axial direction, and the left side of the paper surface in FIG. 3 is defined as the other axial direction. That is, one of the axial directions is the direction opposite to the direction in which the arms 22 and 23 extend from the base 21, and the other in the axial direction is the direction in which the arms 22 and 23 extend from the base 21. Further, among the radial directions, the direction in which the arm portion 22 and the arm portion 23 face each other is defined as the facing direction.

The base 21 is joined to the lower end of the steering shaft 2. The arms 22 and 23 extend from the other end of the base 21 in the axial direction to the other in the axial direction and are connected to the cross axis 13A. The base portion 21 and the arm portions 22 and 23 are integrally formed by, for example, cold forging.

With reference to FIG. 3, the base 21 has a tubular portion 211 and a tightening portion 212.

The tubular portion 211 has a cylindrical shape extending in the axial direction. The tubular portion 211 has a connecting hole 215. The connecting hole 215 is a hole that penetrates the tubular portion 211 in the axial direction. The central axis of the connecting hole 215 coincides with the central axis CL. A female serration 217 is formed on the inner peripheral surface of the tubular portion 211.

It is a pocket surface 218 (see FIG. 5) which is an end surface on the other side in the axial direction of the tubular portion 211, and the inner peripheral surface on the other side in the axial direction of the tubular portion 211 expands from the pocket surface 218 toward one side. A diameterd counterbore portion 219 is provided. Female serrations 217 are not formed on the counterbore 219. By providing the counterbore portion 219, the stress generated at the other end portion of the connecting hole 215 can be relaxed.

The tightening portion 212 is a portion of the base portion 21 that is tightened by the tightening bolt 14A, and projects radially outward (opposite direction) from the outer peripheral side surface of the tubular portion 211. In other words, the direction in which the tightening portion 212 protrudes from the outer peripheral side surface of the tubular portion 211 is the direction in which the arm portion 22 is viewed from the arm portion 23.

FIG. 4 is a front view of the yoke 11A shown in FIG. With reference to FIG. 4, the yoke 11A further has a slit 24. As shown in FIG. 3, the slit 24 penetrates between the inner peripheral surface of the tubular portion 211 and the radial outer surface of the tightening portion 212. That is, the slit 24 penetrates between the inner peripheral surface and the outer peripheral side surface of the tubular portion 211, and also penetrates the tightening portion 212 in the direction perpendicular to the axial direction and the facing direction. As shown in FIG. 4, the slit 24 extends in the axial direction and is open at one end face of the tubular portion 211 and the tightening portion 212 in the axial direction. On the other hand, the other end of the slit 24 in the axial direction is closed. Further, the other end portion of the slit 24 in the axial direction does not extend to the place where the connecting hole 221 is formed, and is closed on the other side of the pocket surface 218 between the pair of arm portions 22 and 23. This makes it possible to prevent the shape of the connecting hole 221 from changing.

The tightening portion 212 has a pair of tightening plates 213,214. The tightening plates 213 and 214 have a plate shape substantially parallel to both the axial direction and the facing direction, and extend radially outward (opposing direction) from the outer peripheral side surface of the tubular portion 211. The tightening plates 213 and 214 face each other with the slit 24 interposed therebetween.

FIG. 5 is a plan view of the yoke 11A shown in FIG. With reference to FIG. 5, the base 21 has a connection portion 216. The connecting portion 216 is located on the opposite side of the tightening plates 213 and 214 with respect to the central axis CL, and protrudes radially outward (opposite direction) from the other end in the axial direction of the tubular portion 211. .. From the other end of the connecting portion 216 in the axial direction, the arm portion 23 extends in the other axial direction.

With reference to FIG. 3, the base 21 further has a bolt insertion hole 26. The bolt insertion hole 26 is formed in the tightening plates 213 and 214 from the tubular portion 211 and is connected to the connecting hole 215. The central axis of the bolt insertion hole 26 formed in the tightening plates 213 and 214 coincides with the central axis SL. The central axis SL is perpendicular to both the axial direction and the opposite direction, and is in a twisted position with the central axis CL.

With reference to FIG. 3, the base 21 further has first recesses 27, 27. The first recesses 27 and 27 are recesses formed on the radial outer surfaces 213a and 214a of the tightening plates 213 and 214. The first recesses 27, 27 extend in the axial direction. The first recess 27 is formed so as to be line-symmetrical with respect to the slit 24.

FIG. 6 is a view of the yoke 11A shown in FIG. 3 as viewed from one axial direction to the other axial direction. In FIG. 6, the female serration 217 is omitted and the yoke 11A is shown.

With reference to FIG. 6, the first recesses 27, 27 extend from one end in the axial direction in which the steering shaft 2 is inserted toward the other end in the axial direction in which the pair of arm portions 22, 23 extend. The tightening plates 213 and 214 are formed in a concave shape toward the connecting hole 215 on the outer surface in the radial direction. The first recesses 27, 27 are open at one end face of the tightening plates 213,214 in the axial direction. As a result, the first recesses 27, 27 can be formed at the same time as the base portion 21, the arm portions 22, 23, etc. at the time of forging, and the forging die and the universal joint yoke 11A after forging can be mutually axially formed. Can be removed.

The other end in the axial direction of the first recesses 27, 27 is closer to one end in the axial direction of the tightening plates 213, 214 than the other end in the axial direction of the slit 24. In the case of the present embodiment, the other end in the axial direction of the first recesses 27, 27, which is one of the recesses, is located on one side of the pocket surface 218 between the pair of arm portions 22, 23. are doing. As a result, the rigidity between the base portion 21 and the arm portion 22 is ensured. Further, the other end of the first recesses 27, 27 in the axial direction is located on one side of the counterbore portion 219. As a result, it is possible to maintain high rigidity in the vicinity of the counterbore portion 219 where stress concentration is likely to occur. Further, since the counterbore portion 219 is located at the base of the two arm portions 22 and 23, it is a place where the twisting force from the two arm portions 22 and 23 is received. If the first recesses 27 and 27 are arranged near the counterbore portion 219, the rigidity around the counterbore portion 219 decreases, and when the twisting force from the two arm portions 22 and 23 is received, the counterbore portion 219 Stress is concentrated. Therefore, the recesses 27 and 27 are arranged apart from the counterbore portion 219 in order to maintain the rigidity around the counterbore portion 219.

Further, the first recesses 27, 27 formed in the tightening plate 213 are opened on the surface of the tightening plate 213 facing the tightening plate 214, respectively. The depth of the first recesses 27, 27 formed in the tightening plate 213 is maximum on the surface of the tightening plate 213 facing the tightening plate 214. The first recesses 27 and 27 are not opened on the outer surfaces of the tightening plates 213 and 214, respectively, and are surrounded by three sides.

The first recesses 27, 27 do not penetrate the radial outer surfaces 213a, 214a of the tightening plates 213,214 and the inner peripheral surface of the bolt insertion hole 26. That is, the maximum depth of the first recesses 27, 27 based on the radial outer surfaces 213a, 214a of the tightening plates 213,214 is outside the radial direction of the tightening plates 213,214. It is smaller than the shortest distance from the side surfaces 213a and 214a to the inner peripheral surface of the bolt insertion hole 26. Further, the maximum depth of the first recesses 27 and 27 is a bolt for the tightening bolt 14A inserted into the bolt insertion hole 26 from the radial outer surfaces 213a and 214a of the tightening plates 213 and 214 in the radial direction. It is longer than the shortest distance to the counterbore 261 (see FIG. 5). The depths of the first recesses 27, 27 gradually decrease from the other side toward the other in the axial direction with respect to the central axis SL corresponding to the central axis of the bolt insertion hole 26.

In the case of the first embodiment, the first recesses 27 and 27 are provided on the radial outer surfaces 213a and 214a of the tightening plates 213 and 214 as recesses, but the tubular portion 211 has a recess. Not provided. As a result, while maintaining the rigidity of the tubular portion 211 in a high state, the distance between the tightening plates 213 and 214 is narrowed by the axial force of the tightening bolt 14A, so that the tubular portion 211 can hold the tip of the steering shaft 2. It is elastically deformed so as to wrap around, and the male serration 2a and the female serration 217 can be strongly engaged with each other.

The arms 22 and 23 are paired and are arranged so as to face each other with the central axis CL interposed therebetween. The arm portions 22 and 23 are arranged so as to be positioned radially outward from the outer peripheral side surface of the tubular portion 211 when viewed in the axial direction. The arm portion 22 extends from the other end of the tightening portion 212 in the base portion 21 in the axial direction to the other in the axial direction. The arm 23 extends axially from the other end of the connecting portion 216 at the base 21 in the axial direction. Connecting holes 221 and 231 for connecting the cross shaft 13A are formed in each of the arm portions 22 and 23.

{4. Joining yoke 11A and steering shaft 2}
The connection between the yoke 11A and the steering shaft 2 will be described with reference to FIG. In addition, in FIG. 5, one in the axial direction corresponds to the upper side shown in FIG. 1, and the other in the axial direction corresponds to the lower side shown in FIG. FIG. 5 shows only the lower end of the steering shaft 2 that is joined to the yoke 11A.

With reference to FIG. 5, the lower end of the steering shaft 2 is inserted into the connecting hole 215 from one axial end of the tubular portion 211 of the yoke 11A. At this time, the steering shaft 2 is formed in the connecting hole 215 so that the male serration 2a formed on the outer peripheral surface of the steering shaft 2 meshes with the female serration 217 formed in the connecting hole 215 of the tubular portion 211 in the yoke 11A. Will be inserted.

Next, the steering shaft 2 inserted into the connecting hole 215 is aligned. As shown in FIG. 5, a continuous groove 2b is formed along the circumferential direction at the lower end portion of the steering shaft 2. The groove 2b is formed at a position where the male serration 2a is divided into two in the axial direction, and is open outward in the radial direction. In the alignment of the steering shaft 2, the position of the bolt insertion hole 26 formed in the yoke 11A and the position of the groove 2b of the steering shaft 2 are aligned in the axial direction.

After the alignment of the steering shaft 2, the tightening bolts 14A are inserted into the bolt insertion holes 26 to tighten the tightening plates 213 and 214. Due to the axial force generated by tightening the tightening bolt 14A, the tightening plates 213 and 214 are elastically deformed so that the width of the slit 24 (size in the center axis SL direction) becomes narrower.

As the width of the slit 24 becomes narrower, the tubular portion 211 is elastically deformed so that the inner diameter of the connecting hole 215 becomes smaller. As a result, the contact area between the inner peripheral surface of the tubular portion 211 and the outer peripheral surface of the lower end portion of the steering shaft 2 becomes larger, and the tightening force increases, so that the yoke 11A and the lower end of the steering shaft 2 become larger. The part is firmly joined.

Further, the tightening bolt 14A inserted into the bolt insertion hole 26 is fitted in the groove 2b of the steering shaft 2. Therefore, the steering shaft 2 is prevented from falling out of the connecting hole 215.

In the yoke 11A, the first recesses 27 and 27 are formed on the radial outer surfaces 213a and 214a of the tightening plates 213 and 214. As a result, the rigidity of the entire base 21 with respect to the deflection can be reduced. That is, by forming the first recesses 27 and 27 on the radial outer surfaces 213a and 214a of the tightening plates 213 and 214, the tubular portion 211 is elastically deformed so that the inner diameter of the connecting hole 215 becomes smaller. It will be easier to do.

As a result, the yoke 11A can prevent the loss of axial force generated by the tightening of the tightening bolt 14A from being reduced as compared with the conventional yoke in which the first recesses 27 and 27 are not formed in the tightening plates 213 and 214. .. Since the contact area between the inner peripheral surface of the base 21 and the outer peripheral surface of the lower end of the steering shaft 2 becomes larger and the tightening force is increased, the yoke 11A and the lower end of the steering shaft 2 are more joined. Can be strengthened.

Further, since the contact area between the inner peripheral surface of the base portion 21 and the outer peripheral surface of the lower end portion of the steering shaft 2 can be increased, the yoke 11A has a gap between the female serration 217 and the male serration 2a. It can be prevented from occurring. Every time the yoke 11A rotates in response to the rotation of the steering shaft 2, the female serrations 217 and the male serrations 2a are prevented from repeatedly contacting each other. As a result, the generation of abnormal noise and the progress of wear of the female serrations 217 and the male serrations 2a can be suppressed, so that the durability of the yoke 11A can be improved.

In the first embodiment, the first recesses 27 and 27 are formed on both the radial outer surfaces 213a and 214a of the tightening plates 213 and 214, but the present invention is not limited to this. The first recess 27 may be formed on any one of the radial outer surfaces 213a and 214a of the tightening plates 213 and 214. Even in this case, since the rigidity of the entire base 21 with respect to the deflection can be reduced, the yoke 11A and the lower end of the steering shaft 2 can be firmly joined.

Further, an example has been described in which the first recesses 27 and 27 formed on the radial outer surfaces 213a and 214a of the tightening plates 213 and 214 are formed line-symmetrically with respect to the slit 24. Not limited to this. The first recesses 27, 27 do not have to be line symmetric. Even in this case, since the rigidity of the entire base 21 with respect to the deflection can be reduced, the yoke 11A and the lower end of the steering shaft 2 can be firmly joined.

As described above, the yoke 11B has the same configuration as the yoke 11A. Therefore, the yoke 11B can strengthen the joint between the tubular portion 211 and the pinion shaft 4, and can improve the durability of the yoke 11B. Further, since the rigidity of the yoke 11B against torsion does not decrease, it is possible to suppress the deformation that occurs when the yoke 11B rotates with the rotation of the pinion shaft 4.

[Second Embodiment]
FIG. 7 is a perspective view of the yoke 30 according to the second embodiment of the present invention. With reference to FIG. 7, the yoke 30 is joined to the lower end of the steering shaft 2 in the same manner as the yoke 11A (see FIG. 2) according to the first embodiment. The yoke 30 may be joined to the upper end of the pinion shaft 4 in the same manner as the yoke 11B shown in FIG.

With reference to FIG. 7, the yoke 30 includes a base 31 and arms 22 and 23. That is, the yoke 30 differs from the yoke 11A in that it includes the base 31 shown in FIG. 7 instead of the base 21 shown in FIG.

The base 31 has the same configuration as the base 21 except that it has a second recess 37 (see FIG. 7) in place of the first recesses 27, 27 (see FIG. 3) of the base 21. That is, in the yoke 30, the first recesses 27 and 27 are not formed on the radial outer surfaces 213a and 214a of the tightening plates 213 and 214.

Hereinafter, the base 31 will be mainly described in terms of differences from the base 21 of the first embodiment, and the description of the configuration common to the base 21 will be omitted.

The second recess 37, which is one of the recesses, is a radial outer surface of the base portion 31 and is a recess formed continuously on the outer peripheral side surface of the tubular portion 211 and the outer peripheral side surface of the connecting portion 216. The second recess 37 is located on the opposite side of the tightening plates 213 and 214 with respect to the connecting hole 215. The second recess 37 does not penetrate between the outer peripheral side surface of the tubular portion 211 and the inner peripheral surface of the tubular portion 211, and the outer peripheral side surface of the connecting portion 216 and the inner peripheral surface of the tubular portion 211. It does not penetrate between.

The second recess 37 extends axially and opens radially outward. The second recess 37 extends to one end of the tubular portion 211 in the axial direction and is open at one end of the tubular portion 211 in the axial direction. The other end of the second recess 37 in the axial direction is closed at the connection portion 216.

By forming the second recess 37 continuously in the tubular portion 211 and the connecting portion 216, the thickness of the outer peripheral side surface and the inner peripheral side surface of the tubular portion 211 in a part of the circumferential direction of the tubular portion 211. Can be made smaller. The tubular portion 211 in which the second recess 37 is formed can have a lower rigidity against bending than the tubular portion 211 in which the second recess 37 is not formed. As a result, the yoke 30 can firmly join the tubular portion 211 and the steering shaft 2 in the same manner as the yoke 11A according to the first embodiment, and can improve the durability of the yoke 30. .. Similar to the yoke 11A according to the first embodiment, since the rigidity of the yoke 30 against torsion does not decrease, it is possible to suppress the deformation that occurs when the yoke 30 rotates with the rotation of the steering shaft 2.

The yoke 30 according to the second embodiment can also be used as a yoke to be joined to the upper end of the pinion shaft 4. Even in this case, the tubular portion 211 and the pinion shaft 4 can be firmly joined, and the durability of the yoke 30 can be improved. Further, since the rigidity of the yoke 30 against torsion does not decrease, it is possible to suppress the deformation that occurs when the yoke 30 rotates with the rotation of the pinion shaft 4.

[Third Embodiment]
FIG. 8 is a perspective view of the yoke 40 according to the third embodiment of the present invention. With reference to FIG. 8, the yoke 40 is joined to the lower end of the steering shaft 2 in the same manner as the yoke 11A (see FIG. 2) according to the first embodiment. The yoke 40 may be joined to the upper end of the pinion shaft 4 in the same manner as the yoke 11B shown in FIG.

With reference to FIG. 8, the yoke 40 includes a base 41 and arms 22 and 23. That is, the yoke 40 differs from the yoke 11A in that it includes the base 41 shown in FIG. 8 instead of the base 21 shown in FIG.

FIG. 9 is a side view of the yoke 40 shown in FIG. 8 as viewed from one axial direction to the other axial direction. In FIG. 9, female serrations 217 are omitted. With reference to FIGS. 8 and 9, the base 41 has a third recess 47, 47, which is one of the recesses, in place of the first recesses 27, 27 of the base 21, except that the base 21 has a third recess 47, 47. Has the same configuration as. That is, in the yoke 40, the first recesses 27 and 27 are not formed on the radial outer surfaces 213a and 214a of the tightening plates 213 and 214. Hereinafter, the base 41 will be mainly described in terms of differences from the base 21 of the first embodiment, and the description of the configuration common to the base 21 will be omitted.

The third recesses 47, 47 are grooves formed on the outer peripheral side surface of the tubular portion 211, extend in the axial direction, and are located between the arm portion 22 and the arm portion 23 when viewed in the radial direction. .. Further, the third recesses 47, 47 are arranged so as to overlap each other in the radial direction. Further, the third recesses 47 and 47 are arranged so as to sandwich the slit 24 with respect to the extending direction of the central axis SL. That is, the third recesses 47, 47 are arranged symmetrically with respect to the central axis CL in the directions orthogonal to both the axial direction and the facing direction. Each of the third recesses 47 and 47 does not penetrate between the outer peripheral side surface of the tubular portion 211 and the inner peripheral surface of the tubular portion 211.

The third recesses 47, 47 are open at one end of the tubular portion 211 in the axial direction. The third recesses 47, 47 are open at the other end of the tubular portion 211 in the axial direction.

By forming the third recesses 47, 47 in the tubular portion 211, the thickness of the outer peripheral side surface and the inner peripheral side surface can be reduced in a part of the tubular portion 211 in the circumferential direction. The tubular portion 211 in which the third recesses 47, 47 are formed can have a lower rigidity against bending than the tubular portion 211 in which the third recesses 47, 47 are not formed. As a result, the yoke 40 can strengthen the joint between the tubular portion 211 and the steering shaft 2 as in the yoke 11A according to the first embodiment, and can improve the durability. Similar to the yoke 11A according to the first embodiment, since the rigidity of the yoke 40 against torsion does not decrease, it is possible to suppress the deformation that occurs when the yoke 40 rotates with the rotation of the steering shaft 2.

In this embodiment, an example in which the third recesses 47 and 47 are formed in the tubular portion 211 has been described, but the present invention is not limited to this. The number of the third recesses 47 formed in the tubular portion 211 may be one. Even in this case, the rigidity of the base 41 against bending can be reduced.

Further, in the present embodiment, an example in which the third recess 47 is opened at one end of the tubular portion 211 in the axial direction and the other end of the tubular portion 211 in the axial direction has been described. Not limited. The third recess 47 may be open at least one end of the tubular portion 211 in the axial direction and the other end portion of the tubular portion 211 in the axial direction. Alternatively, the third recess 47 may not be open at one end of the tubular portion 211 in the axial direction and at the other end of the tubular portion 211 in the axial direction. Even in this case, the rigidity of the base 41 against bending can be reduced. Further, in order to maintain high rigidity in the vicinity of the counterbore portion 219 where stress concentration is likely to occur, the other end portion in the axial direction of the third recess 47 is a pocket surface 218 between the pair of arm portions 22 and 23. The other end of the first recesses 27, 27 in the axial direction may be located on one side of the counterbore portion 219.

The yoke 40 according to the third embodiment can also be used as a yoke to be joined to the upper end of the pinion shaft 4. Even in this case, the yoke 40 and the pinion shaft 4 can be firmly joined, and the durability of the yoke 40 can be improved. Further, since the rigidity of the yoke 40 against twisting does not decrease, it is possible to suppress the deformation that occurs when the yoke 40 rotates with the rotation of the pinion shaft 4.

[Modification example]
In the first embodiment, the example in which the base 21 in the yoke 11A has the first recess 27 and does not have the other recesses has been described, but the present invention is not limited to this. The base 21 in the yoke 11A may have at least one of a second recess 37 and a third recess 47 in addition to the first recess 27. Even in this case, since the rigidity of the yoke 11A against deflection can be further reduced, the joint between the tubular portion 211 and the steering shaft 2 in the yoke 11A can be further strengthened.

Further, the base portion 21 of the yoke 11B shown in FIG. 2 may have at least one of a second recess 37 and a third recess 47 in addition to the first recess 27. Even in this case, since the rigidity of the yoke 11B against deflection can be further reduced, the joint between the tubular portion 211 and the steering shaft 2 in the yoke 11B can be further strengthened.

Further, in the first embodiment described above, in the yoke 11A, an example in which the first recesses 27 and 27 extend axially to the radial outer surface of the tightening plates 213 and 214 has been described. Not limited to. For example, the axial size of the first recesses 27, 27 may be smaller than the radial size. Even in this case, the cylindrical portion 211 and the steering shaft 2 can be firmly joined, and the durability of the yoke 11A can be improved. Further, since the rigidity of the yoke 11A against torsion does not decrease, it is possible to suppress the deformation that occurs when the yoke 11A rotates with the rotation of the pinion shaft 4.

In the above embodiment, the example in which the base portion 21 of the yoke 11A has the connecting portion 216 has been described, but the base portion 21 may not have the connecting portion 216. In this case, the arm portion 23 may extend from the end face of the tubular portion 211 on the other side in the axial direction to the other side in the axial direction.

In the above embodiment, an example in which the yoke 11A is joined to the steering shaft 2 and the yoke 11B is joined to the upper end of the pinion shaft 4 has been described, but the present invention is not limited to this. The yoke 11A may be joined not only to the steering shaft 2 but also to at least one end above and below the intermediate shaft 3.

The universal joint yoke to be joined to the shaft includes a tubular portion, a pair of arm portions, a pair of tightening plates, and a first recess. In the tubular portion, the connecting hole penetrates in the axial direction. The shaft is inserted into the connecting hole from one end of the tubular portion in the axial direction. The pair of arms extends axially from the other end of the tubular portion in the axial direction and faces each other with a connecting hole in between. The pair of tightening plates are arranged so as to face each other so as to sandwich a slit penetrating the inner peripheral surface of the tubular portion and the outer peripheral side surface of the tubular portion, and protrude outward in the radial direction from the outer peripheral side surface of the tubular portion. do. The first recess is formed on the radial outer surface of at least one of the pair of tightening plates.

According to this, the first recess is formed on at least one radial outer surface of the pair of tightening plates, so that the tightening force between the base and the shaft is increased, and the twist of the universal joint yoke is increased. It is possible to reduce the rigidity of the universal joint yoke with respect to bending while ensuring the rigidity against bending.

Further, the universal joint yoke further includes a second recess. The second recess is formed on the outer peripheral side surface of the tubular portion, is located opposite to the pair of tightening plates with the connecting hole interposed therebetween, and extends in the axial direction.

Further, the universal joint yoke further includes a third recess. The third recess is a groove formed on the outer peripheral side surface of the tubular portion and extending in the axial direction.

According to these, a second recess is formed and a third recess is formed. As a result, the tightening force between the base and the shaft is increased, and the rigidity of the universal joint yoke with respect to torsion can be ensured, while the rigidity of the universal joint yoke with respect to bending can be further reduced.

Also, the first recess extends axially on the radial outer surface of at least one of the pair of tightening plates.

According to this, in at least one of the pair of tightening plates, the rigidity against bending can be reduced in the axial direction. Therefore, the rigidity of the universal joint yoke with respect to bending can be further reduced.

Further, the universal joint yoke further includes a connection portion. The connecting portion is located opposite to the pair of tightening plates across the connecting hole and projects radially outward from the other end of the tubular portion in the axial direction. One of the pair of arms extends axially from the connection. The second recess is continuously formed from the outer peripheral side surface of the tubular portion to the outer peripheral side surface of the connecting portion.

According to this configuration, when the universal joint yoke includes a connection portion, a wide area where the second recess is formed can be secured. Therefore, the rigidity of the universal joint yoke with respect to bending can be further reduced.

Further, the third recess is open at one end in the axial direction and the other end in the axial direction of the tubular portion.

According to this configuration, since the length of the third recess in the axial direction can be increased, the rigidity of the universal joint yoke with respect to bending can be further reduced.

Although the embodiment of the present invention has been described above, the above-described embodiment is merely an example for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiment, and the above-described embodiment can be appropriately modified and implemented within a range that does not deviate from the gist thereof.

100 Steering device 1 Steering hole 2 Steering shaft 3 Intermediate shaft 4 Pinion shaft 11A, 11B, 12A, 12B, 30, 40 York 21, 31, 41 Base 22, 23 Arm 27 First recess 37 Second recess 47 Third recess 211 Cylindrical portion 212 Tightening portion 213,214 Tightening plate 215 Connecting hole 216 Connection portion

Claims (5)

A universal joint yoke having a base and a pair of arms extending axially from the other end of the base in the axial direction.
The base is
A cylindrical portion through which the connecting hole penetrates in the axial direction and the shaft is inserted into the connecting hole from one end in the axial direction.
A pair of clamps that are arranged facing each other so as to sandwich a slit penetrating the inner peripheral surface of the tubular portion and the outer peripheral side surface of the tubular portion, and project radially outward from the outer peripheral side surface of the tubular portion. With a veneer,
With a recess formed on the radial outer surface of the base ,
One end of the slit extending in the axial direction on one axial direction opens at one end face in the axial direction of the tubular portion, and the other end in the axial direction is larger than the pocket surface between the pair of arms. Closed on the other side,
The other end of the recess in the axial direction is located on one side of the pocket surface.
The inner peripheral surface of the connecting hole is provided with serrations extending in the axial direction, and the inner circumference of the other end of the connecting hole in the axial direction is provided with a counterbore portion without serrations.
The other end of the recess in the axial direction is located on one side of the counterbore.
Yoke for universal joints. The universal joint yoke according to claim 1, wherein the recess is open at one end surface of the base in the axial direction. The universal joint yoke according to claim 1 or 2 , wherein the first recess, which is one of the recesses, is formed on the radial outer surface of the tightening plate. The universal joint yoke according to claim 3 , wherein the first recess is formed in both of the pair of the tightening plates and is open on the facing surfaces of the tightening plates. Further provided with a bolt insertion hole formed in the tightening plate from the tubular portion,
The universal joint yoke according to claim 3 or 4 , wherein the depth of the first recess gradually decreases from the other side of the central axis of the bolt insertion hole toward the other in the axial direction.

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